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The study of the anodic oxidation of borohydride-ion BH− 4 on catalytically active nickel electrode by methods of potentiostatic inclusion, galvanostatically inclusion, cyclic voltammetry and infrared spectroscopy with Fourier transformation. The composition of some intermediates of the process of electrochemical oxidation of BH− 4 and the mechanism of decomposition of borohydride, which includes the following basic stages: BH− 4 ! BH3(OH)− ! BH2(OH)− 2 ! BH(OH)− 3 ! B(OH)− 4 , is determined. The regularities of the kinetics of the electrochemical oxidation of BH− 4 – ion Ni-electrode is determined. The diffusion coefficient BH−− 4 ion in aqueous solution at a temperature of 25 °C, measured by electrochemical methods, ranges from 5.3·10−5 to 1.6 ·10−5, the average value of 2·10−5 cm2/s.

A methodology for quantitative chemical analysis of the complex “borohydride-borate-hydroxide-carbonate-water” mixtures used as fuel in the borohydride fuel cell was developed and optimized. The methodology includes the combined usage of the acid-base and iodometric titration methods. The acid-base titration method, which simultaneously uses the technique of differentiation and computer simulation of titration curves, allows one to determine the contents of hydroxide (alkali), carbonate, and total “borate + borohydride” content. The iodometric titration method allows one to selectively determine borohydride, so the content of each ofOH-,BH4-,BO2-, andCO32-anions in the fuel becomes estimated. The average determination error depends on the number and ratio of compounds in a mixture. Specific details of the analysis of various fuel mixtures are discussed.